Disposable rotary brush core and filament assembly for power sweepers

ABSTRACT

A disposable cylindrical brush assembly for use in power sweeping machines such as street sweepers. The cylindrical brush is attached to a drive shaft for the machine through use of expansible elastic coupling elements which are carried by the drive shaft and which frictionally engage the inner surface of a cylindrical core which carries the brush filaments.

United States Patent Hunt 1 Mar. 21, 1972 54] DISPOSABLE ROTARY BRUSHCORE 3,097,022 7/1963 Serentz ..29/11'/ x AND FILAMENT ASSEMBLY FOR3,533,?33 3419?; Adams ....l5/l82 34 3 19 Swanson et al. ....15/182 XPOWER SWEEPERS 3,195,159 7/1965 Enchelmaier et a1. ..15/ 179 X [72]Inventor: Frederick B. Hunt, 2559 Pasadena Boulevard wauwatosa, 53226FOREIGN PATENTS OR APPLICATIONS Filed: June 27 Great Britain ..l5/l [21]Appl. No.: 837,052 Primary Examiner-Peter Feldrnan Attorney-Mann, Brown& McWilliams [52] U.S. Cl "115/179, 29/117 [57] ABSTRACT [51] Int. Cl...A46b 1/00 58 Field of Search ..1s 179-1s3; A disposable cylindricalbrush assembly for use in P 29/117 sweeping machines such as streetsweepers. The cylindrical I brush is attached to a drive shaft for themachine through use [56] Reerences cited of expansible elastic couplingelements which are carried by the drive shaft and which frictionallyengage the inner surface of a cylindrical core which carries the brushfilaments.

4 Claims, 9 Drawing Figures PATENTEDHARZI I972 3,649,985

sum 3 [1F 3'- Jkvezz 5'02" DISPOSABLE ROTARY BRUSH CORE AND FILAMENTASSEMBLY FOR POWER SWEEPERS The present invention is directed to new anduseful improvements in rotary brooms of the type used in streetsweepers.

In the past rotary brooms of this type have usually been of a spiralchannel type or a type in which a plurality of circular wafer-likefilament assemblies consisting of circular supports with filaments heldthereon are slipped over a supporting core in the broom. The spiralwound type may be of a type in which a spiral groove is machined in thecore or a type wherein a separate channel is wound about a core withfilaments held in the channel by means of a cord positioned in thechannel and/or by means of clamping pressure from the sides of thechannel. In some spiral wound brushes, a spiral channel and filamentassembly is removably fitted over a core. In both classes of such broomsit has been customary to provide special driving attachments on the coreitself. Sometimes the drive shaft for the broom is formed integrallywith the core. When the drive shaft is formed integrally with the brushcore, the cost of replacing a worn brush is usually more expensive thanis the case where the drive shaft is removable from the brush core andfilament assembly. In the case of brush cores which are removable fromthe drive shaft, the attaching facilities are relatively expensive andcumbersome. The waferlike brush constructions which are removably fittedon a core are relatively expensive and require a relatively large amountof time for removal from and replacement on a core.

With the foregoing in mind, the principal purposes of the presentinvention are to form a brush filament assembly on a cylindrical corewithout any special drive attaching facilities on the core and in such amanner that the replacement channel and filament assembly is in thenormal operating position when received by the purchaser thereof so thatthe purchaser may quickly and easily remove a similarly formed unit fromhis sweeping machine and replace it with a new filament and coreassembly. A related purpose of the invention is to provide simple andeffective means to enable a quick attachment of and detachment of areplaceable filament assembly with drive shaft means of a streetsweeping machine. Another related purpose of the invention is to providea rotary broom in which the cost of material, time and labor inreplacing worn-out filaments is less than in prior machines. These andother purposes of the invention will become more apparent in the courseof the ensuing specification and claims when taken with the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic view of a broom of a power sweeping machineincorporating the principles of the present inventron;

FIG. 2 is another diagrammatic view of the broom shown in FIG. 1 whileillustrating machine driving and supporting means for the broom;

FIG. 3 is another diagrammatic view of a broom as shown in FIG. 1 butillustrating a different driving and supporting means for the broom;

FIG. 4 is a sectional view of the broom or brush core together with anew and improved coupling for coupling the broom drive shaft to thebrush core;

FIG. 5 is a view of the same elements shown in FIG. 4 while illustratinga different operative condition of the elements;

FIG. 6 is a sectional view of a modified form of coupling between thedrive shaft and the brush core;

FIG. 7 is a sectional view of the brush core, coupling and drive shaftshown in FIG. 6 but illustrating a different operative position of theelements illustrated in FIG. 6;

FIG. 8 is a perspective view illustrating the method of assemblingbrooms or brushes formed in accordance with the present invention withthe couplings and drive shaft herein illustrated; and

FIG. 9 is a diagrammatic sectional view of a broom using the couplingsof FIGS. 6 and 7.

Like elements are designated by like characters throughout thespecification and drawings.

With specific reference to the drawings, and in the first instance toFIG. 1, the numeral 10 designates a brush or broom core having brushfilaments 11 fixed thereto and extending radially outwardly therefrom.The filaments 11 as illustrated in FIG. 1 and as used in the inventionmay be fixed to the core through use of a spiral channel wound about thecore and with a cord holding portions of the filaments within thechannel and/or with the channel clamping the filaments, Both in a mannerknown to the art. In lieu of a separate channel member, a channel may bemachined in the exterior surface of the core while using a holding cordto hold the filaments in the channel in a manner known to the art. Thefilaments may also be positioned on the core through use of a pluralityof waferlike" filaments and supports positioned side by side on thecore. In this latter case, relatively short supporting sleeves eachcarry brush filaments extending radially outwardly therefrom and aplurality of the wafer-like" brush elements are positioned side by sidealong the length of the core 11.

In accordance with the invention, the core 10 is hollow and generallycylindrical in form. The core may be made from steel, wood, plastic ormay be fabricated from a plurality of spirally wound laminations ofpaper which are bonded together. The core 10 must be such as to providea substantially smooth inner surface from one end of the core to theother end 10b, while providing approximately the same crosssectionalarea from one end to the other. While the inner surface is smooth, itshould be understood that the material of the core should provide goodfriction with materials such as rubber and resilient polyurethaneplastics. The material used for the core 10 should be sufficiently rigidas to maintain its concentricity and cylindrical shape during subsequentsweeping operations in power sweepers or brooms. In one example, thecore may be approximately eight inches in internal diameter,approximately one-half inch thick and approximately five feet long. Thecore may be formed with other lengths, thicknesses and diameters.

A drive shaft 12 extends through the hollow interior of the core and isfixed to the core through use of spaced couplings l3 and 14 which willbe described hereinafter.

Brooms or brushes as thus described are customarily used with powersweepers of the type having movable or stationary supporting arms forthe drive shaft 12 as illustrated in the alternative drive systems shownin FIGS. 2 and 3. A typical power sweeper is a street sweeping machine.In FIG. 2, for example, the drive shaft 12 is shown as hollow and isprovided with flanges 15 and 16 on the opposite ends thereof. The driveshaft may be solid. The broom supporting arms 17 and 18 may be pivotallymounted on the frame of power sweeping machines so as to enable loweringof the broom to an operative position and raising the broom to aninoperative position in a manner known to the art. In some powersweepers, the supporting arms 17 and 18 may be fixed in the operativeposition. The broom supporting arms carry machine stub shafts 19 and 20which can be coupled with the end flanges 15 and 16 of the drive shaft12. The stub shafts are rotatably mounted in the bearings 19a and 20awhich are carried by the arms 17 and 18. One stub shaft, as for examplestub shaft 19, may carry a drive sprocket which is keyed on stub shaft19 and driven through a chain or belt drive 21 from a suitable primemover on the machine. FIG. 3 illustrates another driving arrangement inwhich the broom or brush supporting arms 17 and 18 carry bearings 21 and22 in which the drive shaft 12 is removably journale d. In thearrangement of FIG. 2, a drive sprocket 23 is keyed to the main driveshaft 12 and driven from the prime mover of the machine. In both FIGS. 2and 3 the sprockets may be inside or outside of the supporting arms.

It should be understood that the invention described herein isapplicable to a number of different drive shaft supporting and drivingmeans. The two different supporting arm and drive arrangements in FIGS.2 and 3 should be taken as illustrative of brush shaft supporting anddriving means known to the art to which the present invention may beapplied.

In accordance with the invention, the brush core with the assembledbrush filaments thereon is removably fixed to the drive shaft throughuse of couplings as illustrated in FIGS. 4-7. In FIG. 4, for example, afirst generally circular clamping plate 23 is positioned around andfixed to the drive shaft as by means of welding or the like. A movableclamping plate 24 surrounds the drive shaft 12 and a disc of rubber orrubberlike material 25 is positioned between the two plates 23 and 24.Disc 24 also surrounds the shaft. The disc 25 may be formed fromresilient natural rubber or synthetic types of neoprene or polyurethaneplastic, possessing good memory characteristics.

TI-Ie fixed plate 23, movable plate 24, and rubber element 25 havenormal diameters providing a clearance with the internal cylindricalsurface of the brush core 10. This diametral clearance may be on theorder of 1/8 to l/IOOO inch so that the brush core is easily slippedover these elements. The inner diameter of the fixed plate 23 should besuch that it makes a rather snug fit with the drive shaft 12. The innerdiameter of the rubber disc 25 preferably should also be such that itmakes a relatively snug fit with the external surface of the drive shaft12, although a small clearance such as several thousandths of an inchmay be used between the disc 25 and shaft 12. The internal diameter ofthe movable plate 24 may be such as to provide a clearance space ofapproximately N16 to H100 of an inch between the plate 24 and theexternal diameter of the shaft 12. Greater and lesser clearances may beused.

The plates 23 and 24 together with the rubber element 25 are held in anassembled position by bolts 26 which are passed through the stationaryplate 23 and threaded into the movable plate 24. A plurality of thesebolts 26 are equally spaced around the shaft. Tightening of the boltscauses the movable plate 24 to move towards the stationary plate 23 andcause the rubber disc 25 to flow outwardly into a tight bindingfrictional engagement with the inner surface of the core. Thiscompressive force exerted by the plates 23 and 24 also causes therubberlike element 25 to press inwardly against the external surface ofthe drive shaft 12. The inward and outward flow tendency of the rubbertends to insure concentricity of the brush core with respect to the axisof the drive shaft 12 because the pressure exerted on the rubber discdevelops radial forces within this element acting both inwardly andoutwardly with respect to the axis of the drive shaft. If the clearancebetween shaft 12 and disc 25 is such that 'the disc 25 does not contactshaft 12 in the expanded or distorted condition of disc 25,concentricity is then established from the fixed position of the bolts26. Such a structure can be used with the removable brush coresdescribed herein, but it is preferred to use a close fit between theshaft and disc to provide the radial forces against the shaft. It shouldbe understood that both couplings 4 I3 and 14 are formed in a manneridentical to the coupling illustrated in FIGS. 4 and 5.

The rubberlike disc 25 may be made in one piece. To facilitate removaland replacement of the disc, the disc may be made in identical halfsections or have a radial slit therein so that it may be removed withoutendwise movement over the shaft.

While it is preferable to fix the stationary plate to the drive shaft12, in some cases it may be advantageous to mount the plate 23 forsliding movement along drive shaft 12 while precluding rotation thereonthrough use of a key or keyway. The particular formation of the coreenables selective positioning of the coupling elements at variouspositions along the drive shaft. This latter type of arrangement may beadvantageous in circumstances wherein different lengths of brush coreassemblies are desired for use on the same drive shaft. After adjustmentof the coupling assemblies at a particular position by sliding movementalong the shaft,'the position lar shoulder 28 which abuts against theend of the brush core 10. A similar abutting fixed plate is used at eachend of the assembly. Again, the fixed plate 27 may be fixed to the driveshaft 12 as by welding or the like, or may be mounted for a slidableadjustment along the length of the drive shaft 12. In FIGS. 6 and 7tightening of the bolts 26 serves to cause the rubberlike element toflow outwardly into a tight frictional driving engagement with the innersurface of the core 10. The form of the invention illustrated in FIGS. 6and 7 may be used with the form illustrated in FIGS. 4 and 5 with acoupling of FIGS. 6 and 7 at one end of the core and a coupling of FIGS.4 and 5 at the other end to permit endwise removal and replacement ofthe brush core over the couplings. A coupling as illustrated in FIGS. 6and 7 may be used at each end of the core if the couplings are removablyfixed to the drive shaft to permit removal and replacement of the core.

In each form of the invention use is made of a brush element in the formof a cylindrical core with brush filaments mounted thereon in a normaloperative position. The assembled core and filaments are easily placedinto a power machine simply by sliding the core over the couplingelements as diagrammatically indicated in FIG. 8, whereupon the bolts 26are tightened to bring about the driving engagement between the shaft 12and the core 10. If the couplings are slidably mounted on the shaft andone or more is removable from the shaft, the coupling or couplings maybe removed from the shaft before the core is removed. Then a new coreunit is placed over the shaft and the removable coupling or couplingsare placed in their normal operative positions. A worn brush unit iseasily replaced simply by loosening the coupling elements whereby thememory of the rubber will cause it to return toward its normal condition(providingclearance between it and the internal surface of the core)whereupon the worn assembled core and filaments are removed from theshaft and couplings by a simple endwise sliding movement. A newdisposable core and filament unit may then be inserted endwise over thecouplings and fixed in position.

The invention makes use of disposable filament and core assembliespractical and economical.

The brush core when removedmay, if desired, be provided with newfilaments as, for example, by removing the filament holding facilitiesfrom the core and then adding new filament holding facilities andfilaments to the core whereupon the core and filament assembly is readyfor reuse in the sweeping machine. A core maybe provided with newfilaments in the case of a spiral channel filament holding assembly asdescribed in US. Pat. to George B. Hunt, No. 3,343,884, by removing theold channel and filaments from the core and thereafter winding a newchannel and group of filament on the core. 7

In each form of the invention, the'inner cylindrical, frictional surfaceof the brush core is the sole drive shaft attaching facility on thecore.

I claim:

1. A heavy duty replaceable rotarybrush and drive assembly for powerstreet sweeping machines and the like including an elongated, hollow,rigid, cylindrical core, said core having a substantially smooth innersurface from end to end thereof and providing an unobstructed passagewayof approximately the same cross-sectional area from end to end of thecore, filament holding means on the exterior surface of the core, brushfilaments carried by said means and extending outwardly from the core, adrive shaft positioned within said core and extending from one end ofsaid core to the other, said drive shaft carrying means providing aconnection with a power source and means providing a connection forsupporting arms of a power sweeping machine, and spaced couplingscarried by said shaft within said core for fixing said core to saiddrive shaft for rotation therewith, each coupling including expansiblerubberlike elements extending around said shaft and platelike elementsembracing each rubberlike element, each coupling having means for movingsaid platelike elements toward one another to cause said rubberlikeelements to bulge outwardly and grip the internal wall of said core in africtional driving engagement, each coupling including means for holdingit on said shaft for rotation therewith, one platelike element of eachcoupling having an outer annular portion engaging one end face of saidcore.

2. A heavy duty replaceable rotary brush and drive assembly for powerstreet sweeping machines and the like including an elongated, hollow,rigid, cylindrical core, said core having a substantially smooth innersurface from end to end thereof and providing an unobstructed passagewayof approximately the same cross-sectional area from end to end of thecore, filament holding means on the exterior surface of the core, brushfilaments carried by said means and extending outwardly from the core, adrive shaft positioned within said core and extending from one end ofsaid core to the other, said drive shaft carrying means providing aconnection with a power source and means providing a connection forsupporting arms of a power sweeping machine, and spaced couplingscarried by said shaft within said core for fixing core to said driveshaft for rotation therewith, each coupling including expansiblerubberlike elements extending around said shaft and platelike elementsembracing each rubberlike element, each coupling having means for movingsaid platelike elements toward one another to cause said rubberlikeelements to bulge outwardly and grip the internal wall of said core in africtional driving engagement, each rubberlike element having a normal,undistorted shape providing a clearance with the internal wall of saidcore and each rubberlike element having an internal aperture with adiameter providing a snug fit with said shaft in the undistorted shapeof the element, whereby, upon movement of said platelike elements towardone another to cause distortion and outward expansion of said elementinto a frictional engagement with the internal wall of said core, saidelement exerts inward pressure against said shaft, each couplingincluding means for holding it on said shaft for rota' tion therewith.

3. The structure of claim 2 characterized by and including means forfixing at least one platelike element of each coupling to said shaft.

4. The structure of claim 2 characterized by and including means forholding each coupling against rotation relative to said shaft.

t i t

1. A heavy duty replaceable rotary brush and drive assembly for powerstreet sweeping machines and the like including an elongated, hollow,rigid, cylindrical core, said core having a substantially smooth innersurface from end to end thereof and providing an unobstructed passagewayof approximately the same cross-sectional area from end to end of thecore, filament holding means on the exterior surface of the core, brushfilaments carried by said means and extending outwardly from the core, adrive shaft positioned within said core and extending from one end ofsaid core to the other, said drive shaft carrying means providing aconnection with a power source and means providing a connection forsupporting arms of a power sweeping machine, and spaced couplingscarried by said shaft within said core for fixing said core to saiddrive shaft for rotation therewith, each coupling including expansiblerubberlike elements extending around said shaft and platelike elementsembracing each rubberlike element, each coupling having means for movingsaid platelike elements toward one another to cause said rubberlikeelements to bulge outwardly and grip the internal wall of said core in africtional driving engagement, each coupling including means for holdingit on said shaft for rotation therewith, one platelike element of eachcoupling having an outer annular portion engaging one end face of saidcore.
 2. A heavy duty replaceable rotary brush and drive assembly forpower street sweeping machines and the like including an elongated,hollow, rigid, cylindrical core, said core having a substantially smoothinner surface from end to end thereof and providing an unobstructedpassageway of approximately the same cross-sectional area from end toend of the core, filament holding means on the exterior surface of thecore, brush filaments carried by said means and extending outwardly fromthe core, a drive shaft positioned within said core and extending fromone end of said core to the other, said drive shaft carrying meansproviding a connection with a power source and means providing aconnection for supporting arms of a power sweeping machine, and spacedcouplings carried by said shaft within said core for fixing core to saiddrive shaft for rotation therewith, each coupling including expansiblerubberlike elements extending around said shaft and platelike elementsembracing each rubberlike element, each coupling having means for movingsaid platelike elements toward one another to cause said rubberlikeelements to bulge outwardly and grip the internal wall of said core in africtional driving engagement, each rubberlike element having a normal,undistorted shape providing a clearance with the internal wall of saidcore and each rubberlike element having an internal aperture with adiameter providing a snug fit with said shaft in the undistorted shapeof the element, whereby, upon movement of said platelike elements towardone another to cause distortion and outward expansion of said elementinto a frictional engagement with the internal wall of said core, saidelement exerts inward pressure against said shaft, each couplingincluding means for holding it on said shaft for rotation therewith. 3.The structure of claim 2 characterized by and including means for fixingat least one platelike element of each coupling to said shaft.
 4. Thestructure of claim 2 characterized by and including means for holdingeach coupling against rotation relative to said shaft.